Fluid ejection devices in inkjet printers provide drop-on-demand ejection of fluid drops. Inkjet printers produce images by ejecting ink drops from ink-filled chambers through nozzles onto a print medium, such as a sheet of paper. The nozzles are typically arranged in one or more arrays, such that properly sequenced ejection of ink drops from the nozzles causes characters or other images to be printed on the print medium as the printhead and the print medium move relative to each other. In a specific example, a thermal inkjet printhead ejects drops from a nozzle by passing electrical current through a heating element to generate heat and vaporize a small portion of the fluid within the ink-filled chamber. In another example, a piezoelectric inkjet printhead uses a piezoelectric material actuator to generate pressure pulses that force ink drops out of a nozzle.
Rapidly refilling the chambers with ink enables increased printing speeds. However, as ink flows into the chambers from a reservoir, small particles in the ink can get lodged in and around the channel inlets that lead to the chambers. These small particles can diminish and/or completely block the flow of ink to the chambers, which can result in the premature failure of heating elements, reduced ink drop size, misdirected ink drops, and so on. As small particles inhibit ink flow to more and more chambers, the resultant failures in corresponding nozzles can noticeably reduce the print quality of a printer.